Isomerases (EC 5)

Enzymes can be classified systematically according to the difference between reaction and substrate specificity, and the mechanism of action. Isomerases (EC 5.x.x.x) are a group of enzymes that catalyze isomerization reactions include the epimerases, racemases, and intramolecular transferases. This process involves the change in bond connectivity or spatial arrangements within a single substrate molecule, generating a product with the same chemical formula (described as an isomer). Isomerases are present in the metabolism and genome of most living organisms, catalysing up to 4% of the biochemical reactions present in central metabolism, in particular, carbohydrate metabolism. There are six isomerase EC subclasses: 1) Racemases, epimerases; 2) Cis-trans isomerases; 3) intramolecular oxidoreductases; 4) intramolecular transferases; 5) intramolecular lyases; 6) Other isomerases. Most of the isomerase reactions are unimolecular (one substrate and one product).